Trips to the Arcus Dam

March 9th 2016 and the Arcus Dam loop July 20th 2016

The structure which I refer to as the Arcus Dam is a small earth dam and associated rock spillway which was built in the 1990’s by Otaki farmer Charles Arcus and his business partner Brian Brassell. The small hydro electricity generating project with an estimated output of 1.5 MW may have been built as a response to a recommendation by the commissioner for the environment who twenty years earlier had suggested the examination of small scale hydro schemes in the Otaki catchment. As I understand the situation a power house was constructed on the true right of the Roaring Meg between the present bridge and the Otaki River but it was damaged/destroyed in a flood. All that remains now of the scheme is an earth dam and a spillway of natural rock. The Roaring Meg is also known as Pukeatua Stream.

What has all this got to do with tramping you may well ask? In March I was to lead a trip to Kime and, with the access road to Otaki forks closed by a slip and an alternative route in available but adding too much time to the trip, an alternative was sought. I knew about the dam but had never visited it and I was also keen to see the slip.

The first of two trips to the area started at the Shield Flat car park and used the DOC alternative route traversing some easy farm land before climbing steeply up a bull-dozed road through a pine plantation. After admiring the view we followed the route through native bush and a very steep descent onto the road leading to the Arcus Dam. Once on the road we followed it past the flat area which was used as an overnight car park prior to construction of the bridge over the Roaring Meg. Once on the Otaki Gorge Road we followed it back towards the slip.

There is a track down to the Otaki River opposite Mr D Campbell’s house. At the river there is a rather expansive area of sand and fine gravel along side the river, an ideal spot for morning tea, which also gave us a very good view of the slip. In a conversation with Mr Campbell I discovered that I had obtained permission to go to the dam from a land owner who did not own the land. Mr Campbell was very helpful and cooperative so we were now able to carry on with the trip and visit the dam.

The road to the dam is in very good condition and is an easy walk through nice native bush. There are very few views into the Roaring Meg until reaching the dam but the ridge on the other side of the Roaring Meg held my attention as a potential extension to this trip. Lunch in the sun at the dam and then returning by the same route, well not quite. Mr Campbell had told us of a better route which his family used and was not quite as steep. (When returning to the area to do a recce for the loop trip it was now the official DOC route and the steepest section had been roped.) The trip had been a bit of a hotch potch but with some points of interest.

The next trip was the loop trip which involved going to the dam and crossing it and following a steepish spur to join the main ridge. Again we left the cars at the DOC car park at Shield Flat but this time made our way over the road past the slip. The benching to try and ensure its future stability is both impressive and extensive (see picture).

After calling in to see Mr Campbell we made our way to the dam for morning tea. After morning tea there was a steep grovel up the side of the spur over loose rocks and through supplejack, the latter playing an important role in assisting the clamber. Once on the spur proper there are bits of tape and a reasonable foot pad, both becoming more sparse as the top of the spur joins the rather featureless ridge line. When doing a recce there was abundant bird song in evidence while climbing this spur. A party of 18 ascending their ridge was a bit much for the bird population. The compass is a useful navigation tool on the rather featureless ridge line in the vicinity of Bump 470 and after a short time some old tapes and a foot pad was found.

From the area around Bump 470 another trip would be to follow the ridge roughly south west to link up with the old fenceline track now the Te Araroa trail. A previous MF TTC day trip in this area had gone further up the Roaring Meg and climbed to the ridge line south west of bump 470. A short distance further on a lunch break was taken where the ridge was heading in an approximately north east direction.

Although the overhead conditions were clear little sun penetrated the bush so we lunched in dappled sunlight. From the lunch spot we followed the twists and kinks of the ridge to the Otaki Forks Road above and on the true right of the Roaring Meg bridge. While walking back to the cars, another slip, which had occurred that morning, was being cleared away by a digger and a couple of trucks … a reminder that any road in such terrain is always prone to such events.